In the development of highly integrated semiconductor circuits there are continuous efforts to design individual or several circuit elements with a miniumum of space, or surface area, on a semiconductor chip. Thereby a maximum number of circuit elements or functions can be provided on a single chip. As known in the art an increase in the degree of integration has a direct positive influence on cost, speed, power, reliability, etc. of the devices fabricated.
U.S. Pat. No. 3,631,311 discloses an integrated semiconductor circuit structure, which provides a transistor with a base leakage resistance directly integrated therewith. There, the resistance zone extends unilaterally into the surrounding isolation area, so that an external resistance contact is no longer required. In a similar configuration according to the publication in the IBM Technical Disclosure Bulletin, Vol. 11, No. 11, April 1969, page 1439, the discharge resistance integrated together with the transistor base is designed as a so-called pinch or dumbbell resistance. Such a pinch resistance is a twice-diffused resistance, where the conductive channel of the actual resistance area is pinched off in its crosssection by the introduction of a further doped area of the opposite conductivity type. Thus, relatively high ohmic resistance values may be obtained, without requiring a relatively sizeable amount of semiconductor surface as required when utilizing bulk resistance.
U.S. Pat. No. 4,005,469 discloses a relatively highly integrated combination of a transistor with an associated anti-saturation diode. An extended metal contact generates simultaneously on the semiconductor surface of one conductivity type an ohmic Schottky contact, and on the surrounding semiconductor surface of a second conductivity type a rectifying Schottkey contact.